Here are a few to try, CostCo has pails that are gluten free cheaper then anyplace else, also try
Food storage and gluten-free food products - Augason Farms CostCo carries some of there stuff for less then their own site...
T & M Enterprises, Storable Food, Emergency Food Storage, AlpineAire Foods
Thrive Food Storage
AAOOB Storable Foods , Long Term Storage Foods for every Budget. Bulk, Wholesale